1. Field of Invention
This invention relates to porous ceramic or refractory products suitable for a variety of applications wherein a porous product is desired. More particularly, the invention concerns a porous ceramic product made of silicon carbide and a method of making the same. The product of the present invention is especially well suited for use in the production of diesel particulate filters.
2. Description of Related Art
Porous ceramic materials are known in the prior art, including porous silicon carbide. Such porous silicon carbide is discussed for example in Shobu et al. U.S. Pat. No. 5,585,313, Atwell et al. U.S. Pat. No. 5,358,910, Gadkaree et al. U.S. Pat. No. 6,555,031 and Way et al. U.S. Pat. No. 6,214,078. Various methods are used to produce porous silicon carbide, but generally, such methods employ a select grade of silicon carbide and elevated firing temperatures that exceed 2300° C.
Porous ceramic materials are used in a variety of applications including high temperature filters as discussed in Way et al.; diffusers as discussed in Veeder et al. U.S. Pat. No. 5,863,031; diesel particulate filters as discussed in Nagi et al. U.S. Pat. No. 5,863,311; Ban et al. U.S. Pat. Nos. 5,961,931 and 6,024,927 and Cheng U.S. Pat. No. 6,835,224; and in armor applications as discussed in Tarpinian U.S. Pat. No. 5,469,773, McCormick et al. U.S. Pat. No. 6,609,452 and Aghajanian et al. U.S. Pat. No. 7,104,177. All twelve of the aforementioned patent documents are incorporated herein by reference
The present invention provides a porous silicon carbide and a method of making the same that offers several distinct advantages over porous products of the prior art. For example, the present invention provides a product that displays uniform porosity and it does not require the use of a special distribution of silicon carbide particles as taught by Way et al. Additionally, the process of the present invention does not require the elevated firing temperatures as taught by Way et al., Shobu et al., Atwell et al. and Gadkaree et al. Further, the porous product of the present invention may be produced without the use of expensive thermoplastic binders as taught by Atwell et al. and Gadkaree et al.